Keytruda biosimilar race heats up with increasing competition

Companies prepare for market entry after 2028 patent expiry

Keytruda ranks No. 1 in Korea, posts KRW 540 billion in sales

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Competition among domestic pharmaceutical and biotech companies is intensifying to secure an early foothold in the biosimilar market for the blockbuster immuno-oncology drug 'Keytruda (pembrolizumab),’ the top-selling drug in Korea.

With Samsung Bioepis accelerating its commercialization efforts by becoming the first Korean company to apply for regulatory approval of a Keytruda biosimilar, later entrants including Alvogen Korea and Celltrion are also challenging patent barriers in hopes of entering the market early.

On the 19th, Alvogen Korea and Celltrion filed a passive trial for scope of rights confirmation (to invalidate or avoid patents) against Keytruda’s formulation patent (Stable formulations of antibodies to human programmed death receptor PD-1, scheduled to expire on March 29, 2032).

MSD Korea’s Keytruda is an immuno-oncology drug that binds to PD-1 and prevents cancer cells from evading the immune system. The drug generated approximately KRW 548.1 billion in distribution and sales in Korea last year, up 13.3% from the previous year, ranking first in the overall Korean pharmaceutical market. Globally, annual sales reached approximately USD 31.7 billion (KRW 46 trillion), making it one of the world’s largest-selling individual drugs.

Given the enormous size of the market both in Korea and globally, competition among biosimilar developers seeking to break the original drug’s exclusivity and enter the market early had to intensify.

Samsung Bioepis leads the biosimilar race…applies for SB27 approval, first in Korea

Samsung Bioepis has taken the lead among Korean developers. The company recently submitted an application to the Ministry of Food and Drug Safety for marketing authorization of its Keytruda biosimilar candidate, SB27.

The application covers 16 indications, including melanoma, non-small cell lung cancer and head and neck cancer. The company demonstrated equivalent efficacy and safety to the original drug through a Phase I trial involving 163 patients in four countries and a Phase III trial involving 555 patients in 14 countries.

Dong-hoon Shin, Executive Vice President of Samsung Bioepis, said, “With this application, we became the first Korean company to enter the regulatory approval process for a Keytruda biosimilar. We will proceed with the review process without delay and work to provide Korean patients with an additional immuno-oncology treatment option as soon as possible.”

Targeting a 2028 early launch… companies seek formulation patent evasion

Alongside the regulatory filing, legal challenges aimed at clearing patent barriers have also emerged. Keytruda’s Korean compound patent (listed in the MFDS Green List),  expires on June 13, 2028. However, its formulation patent, Stable formulations of antibodies to human programmed death receptor PD-1, which runs until March 29, 2032, serves as a secondary barrier.

Even after the compound patent expires, products could remain blocked from launch until 2032 unless developers overcome the formulation patent. Companies are therefore focusing on patent challenges with the aim of launching immediately after the compound patent expires in 2028.

Samsung Bioepis filed a passive trial for scope of rights confirmation against the formulation patent with the Intellectual Property Trial and Appeal Board on Aug. 6. Alvogen Korea and Celltrion followed with challenges to the same patent on Aug. 19. Their filings came within 14 days of Samsung Bioepis’ initial challenge, to join Samsung in the aim of preserving eligibility for first generic exclusivity.

The companies are seeking confirmation that their biosimilars do not fall within the scope of the originator’s formulation patent, allowing them to clear the patent barrier early and enter the market when the compound patent expires in 2028.

As a result, the strategic battle within the pharmaceutical and biotech industry to unlock the patent barriers of the mega-blockbuster Keytruda is expected to heat up even further.